Commit 5d469ec0 authored by Neil Horman's avatar Neil Horman Committed by Linus Torvalds
Browse files

[PATCH] Correct misc_register return code handling in several drivers 



Clean up several code points in which the return code from misc_register is
not handled properly.

Several modules failed to deregister various hooks when misc_register fails,
and this patch cleans them up.  Also there are a few modules that legitimately
don't care about the failure status of misc register.  These drivers however
unilaterally call misc_deregister on module unload.

Since misc_register doesn't initialize the list_head in the init_routine if it
fails, the deregister operation is at risk for oopsing when list_del is
called.  The initial solution was to manually init the list in the miscdev
structure in each of those modules, but the consensus in this thread was to
consolodate and do that universally inside misc_register.

Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Kylene Jo Hall <kjhall@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent dc168427

drivers/char/misc.c

+2 −0
Original line number Diff line number Diff line
@@ -199,6 +199,8 @@ int misc_register(struct miscdevice * misc) 
	dev_t dev;

	int err = 0;



	INIT_LIST_HEAD(&misc->list);



	down(&misc_sem);

	list_for_each_entry(c, &misc_list, list) {

		if (c->minor == misc->minor) {

drivers/char/mmtimer.c

+18 −5
Original line number Diff line number Diff line
@@ -680,7 +680,7 @@ static int __init mmtimer_init(void) 
	if (sn_rtc_cycles_per_second < 100000) {

		printk(KERN_ERR "%s: unable to determine clock frequency\n",

		       MMTIMER_NAME);

		return -1;

		goto out1;

	}



	mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
@@ -689,13 +689,13 @@ static int __init mmtimer_init(void) 
	if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {

		printk(KERN_WARNING "%s: unable to allocate interrupt.",

			MMTIMER_NAME);

		return -1;

		goto out1;

	}



	if (misc_register(&mmtimer_miscdev)) {

		printk(KERN_ERR "%s: failed to register device\n",

		       MMTIMER_NAME);

		return -1;

		goto out2;

	}



	/* Get max numbered node, calculate slots needed */
@@ -709,16 +709,18 @@ static int __init mmtimer_init(void) 
	if (timers == NULL) {

		printk(KERN_ERR "%s: failed to allocate memory for device\n",

				MMTIMER_NAME);

		return -1;

		goto out3;

	}



	memset(timers,0,(sizeof(mmtimer_t *)*maxn));



	/* Allocate mmtimer_t's for each online node */

	for_each_online_node(node) {

		timers[node] = kmalloc_node(sizeof(mmtimer_t)*NUM_COMPARATORS, GFP_KERNEL, node);

		if (timers[node] == NULL) {

			printk(KERN_ERR "%s: failed to allocate memory for device\n",

				MMTIMER_NAME);

			return -1;

			goto out4;

		}

		for (i=0; i< NUM_COMPARATORS; i++) {

			mmtimer_t * base = timers[node] + i;
@@ -739,6 +741,17 @@ static int __init mmtimer_init(void) 
	       sn_rtc_cycles_per_second/(unsigned long)1E6);



	return 0;



out4:

	for_each_online_node(node) {

		kfree(timers[node]);

	}

out3:

	misc_deregister(&mmtimer_miscdev);

out2:

	free_irq(SGI_MMTIMER_VECTOR, NULL);

out1:

	return -1;

}



module_init(mmtimer_init);

drivers/char/tpm/tpm.c

+1 −0
Original line number Diff line number Diff line
@@ -1155,6 +1155,7 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend 


	if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {

		list_del(&chip->list);

		misc_deregister(&chip->vendor.miscdev);

		put_device(dev);

		clear_bit(chip->dev_num, dev_mask);

		kfree(chip);

drivers/input/misc/hp_sdc_rtc.c

+3 −1
Original line number Diff line number Diff line
@@ -695,7 +695,9 @@ static int __init hp_sdc_rtc_init(void) 


	if ((ret = hp_sdc_request_timer_irq(&hp_sdc_rtc_isr)))

		return ret;

	misc_register(&hp_sdc_rtc_dev);

	if (misc_register(&hp_sdc_rtc_dev) != 0)

		printk(KERN_INFO "Could not register misc. dev for i8042 rtc\n");



        create_proc_read_entry ("driver/rtc", 0, NULL,

				hp_sdc_rtc_read_proc, NULL);

drivers/macintosh/apm_emu.c

+2 −1
Original line number Diff line number Diff line
@@ -529,7 +529,8 @@ static int __init apm_emu_init(void) 
	if (apm_proc)

		apm_proc->owner = THIS_MODULE;



	misc_register(&apm_device);

	if (misc_register(&apm_device) != 0)

		printk(KERN_INFO "Could not create misc. device for apm\n");



	pmu_register_sleep_notifier(&apm_sleep_notifier);

CRA Git | Maintained and supported by SUSTech CRA and CCSE